. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. 217 Amongst the calcareous Sponges, the simple Sponge with inhalent pores and terminal osculum {Olyntlms-iovm) is represented by the stock-forming Leucosolenia (Grantia), which is composed of numerous hollow cylinders. The structure of this sponge has been described by Lieberkiihn. In the Syconidai the body cavity has a more complicated form. The central space opens into secondary pei-ipheral spaces or radial tubes, which are lined by ciliated cells, and open externally through the inhalent pores (f
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. 217 Amongst the calcareous Sponges, the simple Sponge with inhalent pores and terminal osculum {Olyntlms-iovm) is represented by the stock-forming Leucosolenia (Grantia), which is composed of numerous hollow cylinders. The structure of this sponge has been described by Lieberkiihn. In the Syconidai the body cavity has a more complicated form. The central space opens into secondary pei-ipheral spaces or radial tubes, which are lined by ciliated cells, and open externally through the inhalent pores (fig. 162). In other calcareous Sponges {Leuconidw) the I'adial canals have the form of irregular parietal canals, giving off branches to the periphery and possessing dilated, ciliated chambers. This form of internal canal system is also found in most of the stock-forming, silicious Sponges (fig. 163). Sponge forms may become more complicated by the formation of stocks ; the originally simple Sponge, which has developed from a single cili- ated larva, gives rise by budding and incomplete fission to a polyzoid sponge body; or .several originally separate individu - als, each of which has origi- nated from a single fuse together to form a com- pound sponge stock. Both these methods of growth are repeated in a similar manner in the formation of the stocks of Polyps (fig. 164). In the same way that the fan-like Fig. 163.—Section of Cor-fjcmm can&'ZaJrK)» (after netS of the Fan Coral (B/u'pi- Fr. E. Schulze). Qk, Ciliated chamber of tlic 7 • ji i n \ s ,„ ^ paxietal canal. dogorgia Jlabelhwi) are fovmed by the repeated fusion of its branches, the gastrovascular cavities of which anastomose, so also in the case of the branching sponges, as a result of the same pro- cess, reticulate, or coiled or even massive stocks are formed (fig. 165),. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
